Making neural connections 1 Flashcards
How do neurons establish connections with their targets?
Sending axons
Why is making connections via axons to neuronal targets important?
Synapse formation and communication
Neuronal survival
Main way that axon pathfinding is driven?
Cytoskeleton modification in the growth cone
What makes up the core of the axon?
Microtubules
What extend out of the growth cone?
Microtubules surrounded by actin filaments
What “provides the motor”–> drives the movement of the growth cone?
Actin
Role of microtubules in the growth cone?
Stabilise the axon behind the growth cone, and allow it to grow
What are filopodia and lamellipodia?
Extensions of the plasma membrane, out of the growth cone
Dynamic, adhesive structures
What controls the shape changes in the growth cone?
The integration of environmental signals (picked up by the filopodia and lamellipodia)
What drives the directionality of movement?
Growth cone shape changes
How is the stabilisation of actin specific?
The stabilization is v localised–> some parts are stabilized while others are not
WHat happens to stabilized/unstabilized actin filaments?
Stabilized ones remain while unstabilized ones do not
Two signals that a growth cone can receive?
Attractive/repulsive
What happens to filapodium when a growth cone nears attractive signals?
It will go towards them, so the filmpodium near them will grow while the filapodium away from them will shrink
What happens as a result of stabilization of actin filaments?
They elongate
How does the directionality of a growth cone come about?
The response to the environmental signals by the actin cytoskeleton
What does the adhesion of the growth cone allow it to do?
Grow and stretch
What types of signal can the growth cone respond to?
both contact mediated and chemotropic guidance cues that are either attractive or repulsive.
What is in the membrane of a growth cone that helps it with directionality?
Receptor for guidance cues
WHat does cytochalasin B do?
Bind to monomeric actin and blocks actin polymerisation, and induces depolarization of filaments
What does phalloidin do?
stabilizes actin filaments and prevents filament depolymerization
What happens if cytochalasin B or phalloidin are artificially added to a growth cone?
Disrupts the proper growth and directionality of the growth cone
How is the axon elongated (stretched)?
Microtubule growth
How does microtubule growth work?
The ends of the microtubule grow as the growth cone grows
